1. Technical Field
The present invention relates to piling and pile driving and more particularly relates to composite timber pile constructions and splice elements therefor. Even more particularly, the present invention relates to a composite timber pile construction and a method of driving composite timber piles in which a splice element confines a displaceable leveling material in a lateral direction with the leveling material transferring load evenly between the two piles spliced.
2. General Background
In various areas of the country where bearing pressures of soil are low and/or unsuitable for building purposes, construction can employ the use of one or more elongated load carrying elements referred to in the industry as a pile or piling. These devices for transferring load between a building and the underlying earth can be concrete, steel, or timber, in construction.
Timber piling are usually somewhat restricted in length because of the very nature of their source, namely trees. Thus it is desirable to splice timber piling together to form piling of extended length. These timber piling can also vary in diameter from end to end, complicating the splicing operation.
Often times timber pile are combined with piling of other construction such as, for example, concrete.
For example, in U.S. Pat. No. 3,003,323 issued to A. R. Holt provides a "Composite Pile Connector".
A "Pile Splicer" is also the subject of U.S. Pat. No. 3,802,206 issued to Robert Moore, et al. In that patent a splicing means for connecting two wood piles end to end to make a long pile for the transfer of pile loads to a lower stronger ground is disclosed. The splicer in that patent provides a plate-like, substantially horizontal element adapted to lie between adjacent pile ends. Optional epoxy glue between the upper and lower surfaces can be provided of the element and the upper and lower piles. A central upright dowel member extends above and below the plate-like element driven into each pile element respectively.
A "Composite Pile and Method of Manufacture" is the subject of U.S. Pat. No. 4,252,473 issued to Albert M. Thomas, et al. The composite section includes a wooden section and a helically corrugated shell secured to the wooden section by a transition fitting.
A composite concrete and timber pile is the subject of U.S. Pat. No. 1,471,124 entitled "Means for Connecting Ferro or Reinforced Concrete Piles to Wooden Piles".
"Composite Piles and Joiners Therefor" is the subject of U.S. Pat. No. 2,912,829 issued to W. H. Cobi. The Cobi patent shows a composite concrete and timber pile with a splice element therefor.
A "Method and Apparatus for Splicing Replacement Pile Sections to a Pile Stub" is the subject of U.S. Pat. No. 3,720,068 issued to E. R. DeRosa.
A splice element for two wooden utility poles, for example, is provided in U.S. Pat. No. 4,032,244. The extension would be attached to the flatten top of an existing pole. A projecting center shaft extends for the bracket to be received within mating center bores provided in the utility pole, a wooden extension pole or both. Threaded fasteners and metal straps complete the interconnection between the existing pole and the extension pole.
A "Pile Coupling and a Method of Pile Driving" is seen in U.S. Pat. No. 3,762,173 issued to Richard Marsh. The patent discloses a means for coupling sections of pile and a method of driving pile utilizing a thin-wall composite pile section. The coupling comprises a thin-wall sleeve with a telescoping thick-wall ring or collar mechanically anchored within the sleeve. Taps integrally formed in the collar, or the entire collar itself, are expanded within the sleeve to form corresponding anchor pots in the sleeve thereby mechanically interlocking the collar and sleeve. The coupling is adapted for use in coupling successive sections of thick-wall tubular pile or in coupling thin-wall tubular composite pile or thick-wall tubular pile. Use of the thin-wall tubular composite pile enables employment of a method for driving which eliminates the necessity for retaining a succeeding thick-wall tubular pile after the initial one is driven home.
The above devices fail to provide a suitable means for effective transfer of load between two timber pile in a manner which is simple, straightforward, easy to use, easy to field erect, easy to duplicate with good load carrying consistency, and easy to adapt to partial shop assembly, providing partial assembly when weather prevents pile driving such as rain, and the like.
In attempting to prepare a composite pile construction of two timber pile sections, invariably the end of the pile provide cut surfaces which may have been the result of a crude cutting arrangement such as a chainsaw or the like. The chances of both pile surface which abut upon assembly being exactly face to face is slim thus preventing the effective transfer of load from one pile to the other. This produces point stresses and can introduce bending moment into the entire assembly of the two pile sections. Such introduction of bending moment into the pile can cause buckling of the entire pile assembly and thus failure upon driving. Indeed, angular misalignment between the two pile sections reduces its effective load carrying capabilities.
Another problem in the assembly of two timber pile sections in a composite fashion is vertical alignment. The two timber pile sections must be vertically aligned and kept vertically aligned during driving so that the shock applied to the entire assembly by a hammer or other driving means does not cause the two piles to shift preventing effective load transfer from the top pile to the bottom pile section.
A composite section of two timber piles should be cost effective. It would be desirable to have an economical composite pile assembly doing away with the need for a concrete and timber pile construction having a timber pile topped with a concrete cap as is often used in the prior art.